App1, App2, … Appn -> each app in its own hardware address space
OS Service and Devices Drivers -> os in its own hardware address space
Hardware -> managed by the OS
Dos-like
Microkernel-based
Monolithic
SPIN mechanisms for event
event-based communication model
event – spin dispatcher, event handlers
Ping, rpc, fwd, http
icmp, udp, tcp
ip pkt arrive
ip
ethernet pkt, atm pkt
default core services in spin
Memory management
-physical address
* allocate, deallocate, reclaim
-virtual address
* allocate, deallocate
-translation
* create/ destory AS, add/remove mapping
-Event handler
* page fault, access fault, badd address
CPU scheduling
-spin abstraction:strand
* semantics defined by extension
-event handlers
* block, unblock, checkpoint, resume
-spin global scheduler
* interact with appliction
